The pop singer's holiday effort will easily spent a fourth week atop the Billboard 200 next week, so say industry sources, which project that the album will sell around 450,000 to 500,000 copies by week's end on Sunday, Dec. 18.

After only seven weeks on sale, "Christmas" has sold 1.52 million in the U.S. according to Nielsen SoundScan -- making it the year's fourth best-selling album. It follows Adele's "21" (5 million), Lady Gaga's "Born This Way" (2 million) and Lil Wayne's "Tha Carter IV" (1.8 million).

As for what debuts will grace the Billboard 200 next week, look for arrivals from Anthony Hamilton's "Back to Love," Metallica's new iTunes-exclusive four-song EP "Beyond Magnetic" and Snoop Dogg and Wiz Khalifa's "Mac & Devin Go to High School" soundtrack.

Hamilton's last release, 2008's "The Point of It All," entered at No. 12 off a 133,000 launch (it was released on Dec. 16, thus profiting from last-minute Christmas shopping). The new album is on course to start with maybe 40,000 to 60,000.

The "Mac & Devin" set -- led by the No. 10 Billboard Hot 100 hit single "Young, Wild & Free" -- could sell around 30,000 to 40,000.

The wild card in the bunch is the Metallica EP. The set is comprised of unreleased songs recorded during the band's "Death Magnetic" album sessions. Because of the unique nature of the set, and its exclusive availability at iTunes for its first week, it's hard to prognosticate what it may ultimately sell in its debut.